In sporty automobiles, especially in sports cars, there often is a need for obtaining an acoustic feedback on the current operating state of the vehicle or of the internal combustion engine. This need occurs above all during acceleration processes, i.e., at upper partial loads as well as at full load of the internal combustion engine. Therefore, a comparatively slight muffling is desired in these operating states. At the same time, the lowest possible exhaust gas back pressure is desired for these operating states in the muffler for the exhaust gas flow in order to be able to obtain the largest amount of power from the internal combustion engine for propelling the vehicle. In contrast to this, it is necessary to achieve the most efficient acoustic muffling possible at a low partial load of the internal combustion engine, especially at idle. Since there is a large excess of power in this operating range of the internal combustion engine, a relatively high back pressure can also be accepted for this in the muffler.
In order for a muffler to be able to meet these conflicting requirements, it is possible to embody in the muffler two exhaust gas paths, one of which can be controlled by means of a control device, while the other is usually uncontrolled. The controllable exhaust gas path is opened at full load, as a result of which the exhaust gas back pressure decreases, By corresponding routing of this controlled exhaust gas path, reduced muffling can also be achieved in this manner. By contrast, the controllable exhaust gas path is blocked at low load, so that the exhaust gas flows only through the uncontrolled path and is efficiently muffled therein. It is, however, problematic in such systems that a comparatively efficient acoustic coupling of the controllable, opened exhaust gas path with the acoustic muffling devices of the muffler is also given at full load, so that a certain muffling is still brought about even at full load.